T-square stabilizer



April 3o, 196s J. E. 'HOYLE T-SQUARE STABILIZER 2 Sheets-Sheet l FiledAug. 22, 1966 KMX INVENTOR.

BY f7/magy April 30, 1968 v J. E. HOYLE 3,380,166

T-SQUARE STABILIZER Filed Aug. 22, 1966 2 Sheets-Sheet 2 United StatesPatent O 3,380,166 T-SQUARE STABILIZER James E. Hoyle, 25408 Highway 66,Barstow, Calif. 92311 Filed Aug. 22, 1966. Ser. No. 580,845 3 Claims.(Cl. 33-80) ABSTRACT OF THE DISCLOSURE A device is disclosed forattachment to a T-square blade so as to cause the T-square head to bepressed firmly against the working edge of the T-square. The devicemaintains the working edge of the T-square blade in alignment with theworking edge of the drawing board. The upper surface of the device canbe constructed so as to form a tray for the storage of supplies such aspencils and erasers. When the device is attached to a moditiedadjustable-head T-square, the T-square can be tilted upward or downward.

The common T-square, which has long been in widespread use as a draftinginstrument, has the disadvantage of being unstable and unreliable fordrawing parallel lines, mainly because the accuracy of the parallelmotion of the T-square blade is dependent upon the alignment of the headof the T-square with the edge of the drawing board. This requires thedraftsman to use one hand to press the T-square head firmly against theboard.

Various modifications in the construction and arrangement of the boardsand T-squares have been devised in attempts to overcome thisdisadvantage. Such modifications have either not worked satisfactorily,or resulted in expensive equipment. Drafting machines which are incommon use in industry, for example, are beyond the price range of theaverage drafting student or draftsman.

It is an object of the present invention, therefore, to provide a novelT-square stabilizer.

It is another object of the present invention to provide a T-squarestabilizer that is simple in construction, easy to manipulate, andinexpensive to manufacture.

It is still another object of the present invention to provide aT-square stabilizer that can be conveniently attached to the blade of aT-square so as to support it resiliently on a drawing board.

It is yet another object of the present invention to provide a T-squarestabilizer that can sustain the T-square on a drafting board so as torelieve the draftsman of all care in connection lwith the support of theT-square head against the edge of the drafting board.

It is yet another object of the present invention to provide a T-squarestabilizer that is suitable for use with a T-square having an adjustablehead.

According to the preferred embodiment of the present invention, astabilizer for converting a T-square into a self-aligning straightedgecomprises a body member having a slot through which passes screw meansfor fastening the stabilizer to the existing hole in the blade of aconventional T-square. A roller is spring-coupled to the body member andexerts pressure on an edge of the drawing board, thereby causing thehead of the T-square to be pressed firmly against the opposite edge ofthe drawing board.

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. The presentinvention, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may best be understood byreference to the following description, taken in connection with theaccompanying drawings, in which:

FIGURE l is an isometric view of a T-square stabilizer according to thepresent invention.

FIGURE 2 is a partly-sectional side view of the T-square stabilizer ofFIGURE l, showing in detail the means by which it is connected to theT-square.

FIGURE 3 shows a different embodiment of the present invention.

FIGURE 4 is a partly-sectional side view of the stabilizer of FIGURE 3.

Turning now to the drawings, FIGURE 1 shows T-square stabilizer 11mounted upon and fastened to blade 13 of T-square 15 by means of knurledthumb nut 17. T-square blade 13 is fastened to T-square head 19 byscrews 21. T-square 15 is shown resting upon drawing board 25, with head19 supported firmly against edge 27 of board 25.

T-square stabilizer 11 has a body member 31, which can be manufacturedas an extruded section having tubular edges 33 and 35, and upright ends37 and 39. Tubular edges 33 and 35 and ends 37 and 39, being upright andabove the fiat central portion 4t) of body member 31, cooperate so as toform an enclosed tray therewith upon the upper surface thereof. Thistray can be used for storing pencils, erasers, etc.

Slot 41 runs along the fiat central portion 46 of body member 31 andextends along a majority of the length thereof, parallel to andequidistant from tubular edges 33 and 35. Slot 41 is used in combinationwith fastening means to facilitate adjustment of the tension applied tothe T-square and also to make it possible to use stabilizer 11 withT-squares of various lengths.

FIGURE 2 shows how screw 43 passes through lightgauge finishing washer45, hole 47 in blade 13, and slot 41, and mates with thumb nut 17.Stabilizer 11 is securely attached to T-square blade 13 by means ofscrew 43. When thumb nut 17 is loosened, stabilizer 11 is free to slidealong blade 13 for the length of slo-t 41. Tape strip 49 is made of acork and rubber composition and has an adhesive backing along surface 51so that it will adhere to the bottom of body member 31. Tape strip 49increases the friction between stabilizer 11 and blade 13.

Rod-like shafts 53 and 55 fit within tubular edges 33 and 35,respectively, and are joined together by cross-tie member 57, so as tobe U-shaped. Shafts 53 and 55 could be manufactured as a single U-shapedmember. Nylon roller or wheel 59 is free to rotate on axle 61, which ismounted upon member 57. Roller 59 lies in a plane parallel to flatcentral portion 40.

The end 63 of each rod-like shaft is coupled to the extreme end of thetubular edge associated therewith, by means of a tension spring 65. Thetension springs 65 will pull shafts 53 and 55 within tubular edges 33and 35, respectively, until member 57 abuts against end 39. The methodof using the T-square stabilizer 11 will now be described.

The draftsman unscrews thumb nut 17 and removes screw 43 and washer 45.The washer 45 is then placed in axial alignment with hole 47 on thebottom surface of T-square blade 13 and screw 43 is insertedtherethrough from the bottom. Stabilizer 11 is positioned upon the topsurface of T-square blade 13 so that screw 43 extends through slot 41.Stabilizer 11 is then moved linearly along the top surface of T-squareblade 13 until it is p0- sitioned such that the forces exerted by thesprings 65 upon shafts 53 and 55 pull roller 59 firmly against the edge71 of drawing board 25.

Thus, the position of stabilizer 11 with respect to blade 13 dependsupon the width of drawing board 25. As a consequence of theconfiguration of stabilizer 11, it can be used with any drawing boardand T-square combination so long as the length of blade 13 projectingfrom head 19 is not in excess of the width of drawing board 25 by morethan approximately the radius of wheel 29, and not less than the widthof board 25 by more than the maximum distance to which wheel 59 can beextended.

Thumb nut 17 is used to fasten stabilizer 11 securely to blade 13. Whenblade 13 is placed upon drawing board 25, it will be separated therefromby the thickness of washer 45. It is important, therefore, that washer45 be as thin as possible, and that the surface of washer 45 in contactwith board 25 be as smooth as possible to mitigate frictiontherebetween. The head of screw 43 should be rccessed within the centralhole of washer 45, so as not to be in contact with board 25. If desired,a countersunk hole can be drilled through blade 13, and screw 43 can beused without washer 45, so that the head of screw 43 will not protrudebeyond the surface of blade 13.

The pressure exerted by roller 59 against edge 71 of board 25 will betransmitted through blade 13 to head 19, and will cause head 19 to bepressed firmly against board 25. The T-square 15 will remain in parallelalignment as it is moved along the edges of board 25. The draftsman willbe relieved of all care in connection with the support of the T-squarehead against the edge 27 of the drafting board 25.

The described stabilizer is adjustable by means of slot 41 and thumb nut17 so that stabilizer 11 can be used with T-squares of various lengths,and can also be adjusted for a variety of different tensions. T-squaresare conventionally manufactured with holes in the extreme end of theblade, for hanging on nails, etc., and stabilizer 11 can be used withthe existing hole. Thus, the stabilizer 11 can be easily attached to anycommon T-square by means of a single stud or screw and nut combination.`

Slot 41 makes it feasible to vary the spring tension on roller 59. Thedraftsman can adjust the tension on roller 59, so that Tsquare 15 can bemoved easily for sketching. The tension can then be changed so thatT-square 15 will be rm and steady for lettering with a lettering guide,as well as adjusted to moderate tension for ordinary drawing. By usingthe described T-square stabilizer, the draftsman will be able to obtainmost of the advantages of a drafting machine for a fraction of the cost.

FIGURES 3 and 4 show another embodiment of the present invention inwhich three countersunk holes are drilled into the end of blade 71 ofthe adjustable-head T-square 73, along a line perpendicular to the edgesthereof. One hole is in the middle and the other two holes areequidistant from the edges of blades 71. Body member 75 of T-squarestabilizer 77 is an extruded section and is fastened to blade 71 byscrew 79, which passes through hole 81. Hole 81, being countersunk,permits the head of screw 79 to be recessed within blade 71, and not toprotrude below the bottom thereof.

When the T-square 73 is used as a conventional T-square, the centralhole is used. When the T-square 73 is tilted upward, as shown in FIGURE3, the bottom hole 81 is used, as shown, so that the end of stabilizer77 does not extend beyond the upper edge of T-square blade 71, whichmight interfere with the use thereof for drafting. When T-square 73 istilted downward, the upper hole is used and stabilizer 77 is tiltedupward.

The significance of the described embodiment is that in the case of anadjustable-head T-square, it is important to align the pivot point 83 inthe head 85 with the point of contact between roller 87 and board 89.Thus, the more closely line 93, which passes between those points, isaligned perpendicularly to side 91 of board 89, the more stable theT-square will be While particular embodiments of the present inventionhave been shown and described, it will be obvious to those skilled inthe art that changes and modifications may be made without departingfrom this invention in its broader aspects, and, therefore, the aim inthe appended claims is to cover all such changes and modifications asfall within the true spirit and scope of this invention.

l claim:

1. A stabilizer for a T-square having at least one hole in an end of theblade thereof, comprising:

(a) a main-body member having a substantially flat surface lying in afirst plane, a recessed surface opposite said flat surface forsupporting objects thereon, and a linear slot passing through said bodymember and extending along a major portion of th length thereof',

(b) fastening means coupled to said body member for securing said bodymember to said T-square blade through said slot and said hole in saidblade; and

(c) support means for coupling said blade to an edge of a drawing board,said stabilizer' causing the head of said T-square to be pressed firmlyagainst the opposite edge of said board when so coupled, said supportmeans including a single wheel-like roller means coupled to saidmain-body member by spring means, said roller means being rotatable in aseecnd plane parallel to said first plane, and extendable linearly alongsaid second plane, said roller means being coupled to said spring meansby a pair of rod-like shaft means, each shaft means fitting slidablywithin a tubular edge of said body member, and said recessed surfacehaving enclosing sides formed by said tubular edges and upright endmembers.

2. Apparatus as defined in claim 1 in which said head of said T-squareis pivotable with respect to said T-square blade, which has threecountersunk holes drilled therein linearly across the distal end of saidblade for attachment of said stabilizer therethrough.

3. A stabilizer for converting aligning straightedge, comprising:

(a) a main-body member having a substantially flat surface lying in afirst plane, and a linear slot passing therethrough and extending alonga major portion of the length thereof, the blade of said T-square havinga plurality of holes provided transversely across the distal endthereof;

(b) fastening means coupled to said body member for securing said bodymember to said T-square blade through said slot and one of saidplurality of holes in said blade; and

(c) support means for coupling said blade to an edge of a drawing board,said stabilizer causing the head of said T-square lo be pressed firmlyagainst the opposite edge of said board when so coupled, said supportmeans including rotatable roller means lying in a second plane parallelto said first plane, said roller means being coupled to said main-bodymember by spring means.

a T-square into a self- References Cited FOREIGN PATENTS 13,744 1913Great Britain.

13,943 1904 Great Britain.

24,635 1893 Great Britain. 819,372 10/ 1951 Germany.

HARRY N. HAROIAN, Primary Examiner.

